Two potassium efficient genotypes (HEK-1,HEK-2) of potato (Solanum tuberosum L.) were used to study the potassium utilization mechanism by determination of yield of fresh tuber,biomass and potassium uptake in different parts of the plant,kinds and concentrations of organic acids in root exudes,and the potassium release ability of root exudes under hydroponic and sand cultivation conditions.The results showed that compared to CK,in the low potassium concentration,HEK-1 could keep higher yield of dry mater of root; at every growth period higher potassium content was maintained in the stalk and at the maturation period,the plant potassium utilization efficiency was the highest of all ; HEK-2 at low potassium level,the content of ethanedioic acid in organics what was secreted by the root was higher than that of HEK-1 and CK,and it can activate potassium in surrounding soil better than other two materials.%为探索马铃薯钾高效机制,利用营养液沙基盆栽方法,对比研究了不同钾处理下2个钾高效材料(‘HEK-1’和‘HEK-2’)和1个普通品种(‘合作88,)的单株鲜薯产量、植株各部位在不同生长时期的干物质和钾素积累量、根系分泌有机酸种类与含量以及根系分泌物对土壤中钾的活化能力等评价作物钾效率的相关指标.结果表明,与普通品种相比,低钾浓度下,‘HEK-1’保持较高的根系干物重,各生长时期地上茎中均保持较高的钾含量,成熟期植株钾利用效率高；‘HEK-2’低钾胁迫下根系分泌物中草酸含量较多,其根系分泌物活化土壤中钾的能力强.结论:不同基因型的钾高效材料耐低钾机制不同,提高植株钾利用效率或增加根系分泌物中的草酸含量以促进钾吸收都属于马铃薯应答低钾胁迫的有效方式.
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